Signal processing apparatus, signal processing method, and program

ABSTRACT

In a signal processing apparatus, when a luminance signal in a first numeric range is assigned to an integer value in a second range narrower than a first range representable by predetermined bits, and a luminance signal and color-difference signals are outputted under a predetermined standard in which a color-difference signal in a second numeric range is assigned to an integer value in a third range narrower than the first range, the luminance signal in the first numeric range is assigned to an integer value in a fourth range between the first and second ranges; the color-difference signal in the second numeric range is assigned to an integer value in a fifth range between the first and third ranges; and the fourth range is adjusted in a range between the first range and second range, and the fifth range is adjusted in a range between the first and third ranges.

CROSS REFERENCES TO RELATED APPLICATIONS

The present invention contains subject matter related to Japanese PatentApplication JP 2006-251135 filed in the Japanese Patent Office on Sep.15, 2006, the entire contents of which being incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a signal processing apparatus, a signalprocessing method, and a program, particularly to a signal processingapparatus, a signal processing method, and a program which can representcolors in a color gamut wider than a color gamut before in video signalprocessing.

2. Description of the Related Art

Data compression processing compliant to ITU-R (InternationalTelecommunication Union Radiocommunication sector) BT (Broadcastingservice (Television)).709 (hereinafter, simply referred to as BT.709(see Non-Patent Reference 1 (RECOMMENDATION ITU-R BT.709-4)) will bedescribed.

For example, in video cameras, color signals are obtained by imaging,and then subjected to A/D conversion, and color signals R, G and B thusobtained are converted into color signals R, G and B in primary colorsbased on primary colors according to BT.709.

The color signals R, G and B converted in primary colors are correctedto color signals R, G and B in the numeric range of 0 to 1.0 defined byBT.709. In other words, for example, the color signals R, G and Bsmaller than zero are corrected (clipped) to zero, whereas the colorsignals R, G and B greater than 1.0 are corrected to 1.0. In addition,here, suppose that 0 and 1.0 in the numeric range of 0 to 1.0 are theminimum value and the maximum value of the color signals R, G and Bcompliant to BT.709, respectively.

The color signals R, G and B corrected to the numeric range of 0 to 1.0are converted into the color signals R, G and B that are corrected by γ(the nonlinearity of luminous brightness for image signals) of a displaymechanism of BT.709 in accordance with the photoelectric conversionproperties compliant to BT.709.

The photoelectric conversion properties here are defined in the range ofthe minimum value to the maximum value of the color signals R, G and Bcompliant to BT.709, that is, 0 to 1.0.

The color signals R, G and B corrected by γ (the nonlinearity ofluminous brightness for image signals) of the display mechanism ofBT.709 are converted into a luminance signal Y and color differencesignals CB/CR compliant to BT.709.

According to BT.709, the luminance signal Y obtained here has the valuein the numeric range of 0 to 1.0. In addition, the color differencesignals CB/CR have a value in the numeric range of −0.5 to 0.5.

The luminance signal Y and the color difference signals CB/CR convertedin compliance with BT.709 are represented by eight bits.

More specifically, as shown in FIG. 1A, the luminance signal Y in thenumeric range of 0 to 1.0 is assigned to integer values in the integerrange of 16 to 235 that is narrower than the integer range of 0 to 255representable by eight bits.

In other words, to the luminance signal Y, eight bits of integer valuesare assigned so that the undershoot region of 1 to 15 and the overshootregion of 236 to 254 are provided.

Moreover, as shown in FIG. 1B, the color difference signals CB/CR in thenumeric range of −0.5 to 0.5 are assigned to integer values in theinteger range of 16 to 240 that is narrower than the integer range of 0to 255 representable by eight bits.

In other words, to the color difference signals CB/CR, eight bits ofinteger values are assigned so that the undershoot region of 1 to 15 andthe overshoot region of 241 to 254 are provided.

In addition, in the luminance signal Y and the color difference signalsCB/CR, 0 and 255 are not used.

The luminance signal Y having such integer values is encoded inaccordance with a predetermined format such as MPEG (Moving PictureExperts Group) as the luminance signal compliant to BT.709, and thecolor difference signals CB/CR having integer values are encoded inaccordance with the same format as the luminance signal, as the colordifference signal compliant to BT.709. The encoded data thus obtained isrecorded on a recording medium, or outputted on a network.

As described above, the color signals are processed in accordance withthe BT.709 standards, whereby a television set can process the colorsignals in compliance with BT.709.

SUMMARY OF THE INVENTION

In recent years, such a display device is developed that can display theluminance signal Y and the color difference signals CB/CR in theovershoot region and the undershoot region, in the luminance signal Yand the color difference signals CB/CR, that is, for example, that canrepresent colors in a wider color gamut than that represented incompliance with predetermined standards such as BT.709.

However, in the data compression method described above, since theluminance signal Y and the color difference signals CB/CR are notassigned to the overshoot region and the undershoot region, it isdifficult to provide compressed data that meets a display device whichcan represent colors in a wider color gamut.

Thus, it is desirable to provide signals that can represent colors in awider color gamut than that represented in compliance with predeterminedstandards such as BT.709.

A signal processing apparatus according to an embodiment of theinvention is a signal processing apparatus in which a luminance signalin a first numeric range is assigned to an integer value in a secondinteger range that is narrower than a first integer range representableby a plurality of predetermined bits for representation, and a luminancesignal and color difference signals are outputted in compliance with apredetermined standard in which a color difference signal in a secondnumeric range is assigned to an integer value in a third integer rangethat is narrower than the first integer range for representation, thesignal processing apparatus including: a luminance signal assigningmeans for assigning the luminance signal in the first numeric range toan integer value in a fourth integer range that is narrower than thefirst integer range and wider than the second integer range; a colordifference signal assigning means for assigning the color differencesignals in the second numeric range to an integer value in a fifthinteger range that is narrower than the first integer range and widerthan the third integer range; and an adjusting means for adjusting thefourth integer range in a range that is narrower than the first integerrange and wider than the second integer range, and adjusting the fifthinteger range in a range that is narrower than the first integer rangeand wider than the third integer range.

A signal processing method according to an embodiment of the inventionis a signal processing method in which a luminance signal in a firstnumeric range is assigned to an integer value in a second integer rangethat is narrower than a first integer range representable by a pluralityof predetermined bits for representation, and a luminance signal andcolor difference signals are outputted in compliance with apredetermined standard in which a color difference signal in a secondnumeric range is assigned to an integer value in a third integer rangethat is narrower than the first integer range for representation, thesignal processing method including the steps of: assigning the luminancesignal in the first numeric range to an integer value in a fourthinteger range that is narrower than the first integer range and widerthan the second integer range; assigning the color difference signals inthe second numeric range to an integer value in a fifth integer rangethat is narrower than the first integer range and wider than the thirdinteger range; and adjusting the fourth integer range in a range that isnarrower than the first integer range and wider than the second integerrange, and adjusting the fifth integer range in a range that is narrowerthan the first integer range and wider than the third integer range.

A program according to an embodiment of the invention is a program whichallows a computer to execute an output process in which a luminancesignal in a first numeric range is assigned to an integer value in asecond integer range that is narrower than a first integer rangerepresentable by a plurality of predetermined bits for representation,and a luminance signal and color difference signals are outputted incompliance with a predetermined standard in which a color differencesignal in a second numeric range is assigned to an integer value in athird integer range that is narrower than the first integer range forrepresentation, the output process including the steps of: assigning theluminance signal in the first numeric range to an integer value in afourth integer range that is narrower than the first integer range andwider than the second integer range; assigning the color differencesignals in the second numeric range to an integer value in a fifthinteger range that is narrower than the first integer range and widerthan the third integer range; and adjusting the fourth integer range ina range that is narrower than the first integer range and wider than thesecond integer range, and adjusting the fifth integer range in a rangethat is narrower than the first integer range and wider than the thirdinteger range.

In the signal processing apparatus, the signal processing method, andthe program according to an embodiment of the invention, in the case inwhich a luminance signal in a first numeric range is assigned to aninteger value in a second integer range that is narrower than a firstinteger range representable by a plurality of predetermined bits forrepresentation, and a luminance signal and color difference signals areoutputted in compliance with a predetermined standard in which a colordifference signal in a second numeric range is assigned to an integervalue in a third integer range that is narrower than the first integerrange for representation, the luminance signal in the first numericrange is assigned to an integer value in a fourth integer range that isnarrower than the first integer range and wider than the second integerrange; the color difference signal in the second numeric range isassigned to an integer value in a fifth integer range that is narrowerthan the first integer range and wider than the third integer range; andthe fourth integer range is adjusted in a range that is narrower thanthe first integer range and wider than the second integer range, and thefifth integer range is adjusted in a range that is narrower than thefirst integer range and wider than the third integer range.

According to an embodiment of the invention, for the signals that can betreated in compliance with predetermined standards such as BT.709, colorsignals in a wider color gamut can be outputted depending on the displayperformance capabilities of display devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B shows a diagram illustrative of the passband of theluminance signal and the color difference signal in accordance withBT.709;

FIG. 2 shows a block diagram depicting an exemplary configuration of adata compressor to which an embodiment of the invention is adapted;

FIG. 3 shows a flow chart illustrative of the operation of an input datapassband control part shown in FIG. 2;

FIG. 4 shows a flow chart illustrative of the operation of a luminanceovershoot passband adjusting circuit shown in FIG. 2;

FIG. 5 shows a flow chart illustrative of the operation of a luminanceundershoot passband adjusting circuit shown in FIG. 2;

FIG. 6 shows a flow chart illustrative of the operation of a colordifference passband adjusting circuit shown in FIG. 2;

FIGS. 7A and 7B show a diagram depicting an exemplary passband accordingto an embodiment of the invention; and

FIG. 8 shows a block diagram depicting an exemplary configuration of acomputer to which an embodiment of the invention is adapted.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an embodiment of according to an embodiment of theinvention will be described. The following is examples of thecorrespondence between configuration requirements for according to anembodiment of the invention and the embodiments of the specification orthe drawings. This is described for confirming that the embodimentssupporting according to an embodiment of the invention are described inthe specification or the drawings. Therefore, even though there is anembodiment that is described in the specification or the drawings but isnot described herein as an embodiment corresponding to configurationrequirements for the invention, it does not mean that the embodimentdoes not correspond to those configuration requirements. Contrary tothis, even though an embodiment is described herein as an embodimentcorresponding to configuration requirements, it does not mean that theembodiment does not correspond to configuration requirements other thanthose configuration requirements.

A signal processing apparatus according to an embodiment of theinvention is a signal processing apparatus in which a luminance signalin a first numeric range (0 to 255) is assigned to an integer value in asecond integer range (for example, 16 to 235) that is narrower than afirst integer range representable by a plurality of predetermined bits(for example, eight bits) for representation, and a luminance signal andcolor difference signals are outputted in compliance with apredetermined standard in which a color difference signal in a secondnumeric range is assigned to an integer value in a third integer range(for example, 16 to 240) that is narrower than the first integer range(for example, 0 to 255) for representation, the signal processingapparatus including: a luminance signal assigning means (for example, aluminance overshoot passband adjusting circuit 12 shown in FIG. 2 or aluminance undershoot passband adjusting circuit 13) for assigning theluminance signal in the first numeric range to an integer value in afourth integer range (for example, 16 to 240) that is narrower than thefirst integer range and wider than the second integer range (forexample, FIG. 7A); a color difference signal assigning means (forexample, a color difference passband adjusting circuit 14 shown in FIG.2) for assigning the color difference signals in the second numericrange to an integer value in a fifth integer range that is narrower thanthe first integer range and wider than the third integer range; and anadjusting means for adjusting (for example, an input data passbandcontrol part 16 shown in FIG. 2) the fourth integer range in a rangethat is narrower than the first integer range and wider than the secondinteger range, and adjusting the fifth integer range in a range that isnarrower than the first integer range and wider than the third integerrange.

A signal processing method, or a program according to an embodiment ofthe invention is a signal processing method in which a luminance signalin a first numeric range is assigned to an integer value in a secondinteger range that is narrower than a first integer range representableby a plurality of predetermined bits for representation, and a luminancesignal and color difference signals are outputted in compliance with apredetermined standard in which a color difference signal in a secondnumeric range is assigned to an integer value in a third integer rangethat is narrower than the first integer range for representation, or aprogram which allows a computer to execute an output process in which aluminance signal in a first numeric range is assigned to an integervalue in a second integer range that is narrower than a first integerrange representable by a plurality of predetermined bits forrepresentation, and a luminance signal and color difference signals areoutputted in compliance with a predetermined standard in which a colordifference signal in a second numeric range is assigned to an integervalue in a third integer range that is narrower than the first integerrange for representation, including the steps of: assigning theluminance signal in the first numeric range to an integer value in afourth integer range that is narrower than the first integer range andwider than the second integer range (for example, Step S13 in FIG. 4 orStep S23 in FIG. 5); assigning the color difference signals in thesecond numeric range to an integer value in a fifth integer range thatis narrower than the first integer range and wider than the thirdinteger range (for example, Step S33 in FIG. 6); and adjusting thefourth integer range in a range that is narrower than the first integerrange and wider than the second integer range, and adjusting the fifthinteger range in a range that is narrower than the first integer rangeand wider than the third integer range (for example, Step S1 to Step S3in FIG. 3).

FIG. 2 shows an exemplary configuration of a data compressor to which anembodiment of the invention is adapted.

A color signal generating circuit 11 subjects color signals R, G and Bobtained by imaging pictures by means of a shooting part, not shown, toA/D conversion, and converts the signals into color signals R, G and Bin primary colors based on primary colors in compliance with BT.709.

The color signal generating circuit 11 subjects the color signals R, Gand B converted in primary colors to photoelectric conversion inaccordance with the photoelectric conversion properties, converts thecolor signals R, G and B after photoelectric conversion into a luminancesignal Y and color difference signals CB/CR, and corrects the luminancesignal Y to a luminance signal in a predetermined numeric range and thecolor difference signals CB/CR to color difference signals in apredetermined numeric range (for example, −0.57 to 0.56).

The color signal generating circuit 11 assigns the luminance signal Yafter corrected to integer values in the integer range of 1 to 254 thatis narrower than the integer range of 0 to 255 representable by eightbits, and outputs the luminance signal Y of the integer values to aluminance overshoot passband adjusting circuit 12.

The color signal generating circuit 11 also assigns the color differencesignals CB/CR after corrected to integer values in the integer range of1 to 254 that is narrower than the integer range of 0 to 255representable by eight bits, and outputs the color difference signalsCB/CR of the integer values to a color difference passband adjustingcircuit 14.

The luminance overshoot passband adjusting circuit 12 adjusts thehighest value (hereinafter, referred to as an upper limit) of thepassband (in the integer range of 1 to 254) of the luminance signal Y inaccordance with control done by an input data passband control part 16.

The luminance overshoot passband adjusting circuit 12 passes theluminance signal Y in the integer range of 1 to 254 supplied from thecolor signal generating circuit 11 through the adjusted passband, andsupplies the luminance signal Y passed through the band to a luminanceundershoot passband adjusting circuit 13.

The luminance undershoot passband adjusting circuit 13 adjusts thelowest value (hereinafter, referred to as a lower limit) of the passband(in the integer range of 1 to 254) of the luminance signal Y inaccordance with control done by the input data passband control part 16.

The luminance undershoot passband adjusting circuit 13 passes theluminance signal Y supplied from the luminance overshoot passbandadjusting circuit 12 through the adjusted passband, and supplies theluminance signal Y passed through the band to a compression circuit 15.

The color difference passband adjusting circuit 14 adjusts the upperlimit and the lower limit of the band (the integer range of 1 to 254) ofthe color difference signals CB/CR by the same size in accordance withcontrol done by the input data passband control part 16 (that is, theupper limit is made smaller by N, whereas the lower limit is madegreater by the same N).

The color difference passband adjusting circuit 14 passes the colordifference signals CB/CR in the integer range of 1 to 254 supplied fromthe color signal generating circuit 11 through the adjusted passband,and supplies the color difference signals CB/CR passed through the bandto the compression circuit 15.

The compression circuit 15 encodes the luminance signal Y supplied fromthe luminance undershoot passband adjusting circuit 13 and the colordifference signals CB/CR supplied from the color difference passbandadjusting circuit 14 in accordance with a predetermined format such asMPEG (Moving Picture Experts Group), and externally outputs the encodeddata thus obtained to a recording medium or a network.

Next, the operation of the input data passband control part 16 will bedescribed with reference to a flow chart shown in FIG. 3.

In Step S1, the input data passband control part 16 requests theluminance overshoot passband adjusting circuit 12 to change the upperlimit of the band for the luminance signal Y to a predetermined value inaccordance with the display performance capabilities of a display device(hereinafter, referred to as a target display device), not shown, thatdisplays data compressed in a data compression process to be performed,for example. In addition, in the case in which no changes are necessary(that is, in the case in which the upper limit of the luminance signal Ycorresponding to the display performance capabilities of the targetdisplay device is 254), this is notified.

In Step S2, the input data passband control part 16 requests theluminance undershoot passband adjusting circuit 13 to change the lowerlimit of the band for the luminance signal Y to a predetermined value inaccordance with the display performance capabilities of the targetdisplay device. In addition, in the case in which no changes arenecessary (that is, in the case in which the lower limit of theluminance signal Y corresponding to the display performance capabilitiesof the target display device is 1), this is notified.

Subsequently, in Step S3, the input data passband control part 16requests the color difference passband adjusting circuit 14 to changethe range of the passband for the color difference signals CB/CR to apredetermined range corresponding to the range of the displayperformance capabilities of the target display device. In addition, inthe case in which no changes are necessary (that is, in the case inwhich the band of the color difference signals CB/CR corresponding tothe display performance capabilities of the target display device isfrom 1 to 254), this is notified.

As described above, the luminance overshoot passband adjusting circuit12, the luminance undershoot passband adjusting circuit 13 and the colordifference passband adjusting circuit 14 are requested to change (thatis, adjust) the passbands for the luminance signal Y and the colordifference signals CB/CR, and then the process is ended.

Next, the operation of the luminance overshoot passband adjustingcircuit 12 will be described with reference to a flow chart shown inFIG. 4.

In Step S11, the luminance overshoot passband adjusting circuit 12determines whether the input data passband control part 16 makes arequest for changing the upper limit of the passband for the luminancesignal Y in Step S1 in FIG. 3. If it determines that a request is made,it goes to Step S12.

In Step S12, the luminance overshoot passband adjusting circuit 12determines whether the value of the luminance signal Y is greater thanthe requested upper limit of the passband. If it determines that thevalue is greater, it goes to Step S13, and clips (corrects) the value ofthe luminance signal Y now inputted to the same value as the upperlimit.

If it is determined that no request is made for changing the upper limitof the passband in Step S11 (that is, if it is notified that the upperlimit is not changed), if it is determined that the value of theluminance signal Y now inputted is equal to or below the upper limit ofthe passband in Step S12, or if it is determined that the value of theluminance signal Y is clipped to the upper limit of the passband in StepS13, the luminance overshoot passband adjusting circuit 12 goes to StepS14, and outputs the value of the luminance signal Y to the luminanceundershoot passband adjusting circuit 13.

In Step S15, the luminance overshoot passband adjusting circuit 12determines whether the luminance signal Y is inputted from the colorsignal generating circuit 11. If it determines that the luminance signalY is inputted, it returns to Step S11, and similarly performs theprocess steps after that for the inputted luminance signal Y.

If it is determined that the luminance signal Y is not inputted from thecolor signal generating circuit 11 in Step S15, the luminance overshootpassband adjusting circuit 12 ends the process.

Next, the operation of the luminance undershoot passband adjustingcircuit 13 will be described with reference to a flow chart shown inFIG. 5.

In Step S21, the luminance undershoot passband adjusting circuit 13determines whether the input data passband control part 16 makes arequest for changing the lower limit of the passband for the luminancesignal Y in Step S2 in FIG. 3. If it determines that a request is made,it goes to Step S22.

In Step S22, the luminance undershoot passband adjusting circuit 13determines whether the value of the luminance signal Y now inputted issmaller than the requested lower limit. If it determines that the valueis small, it goes to Step S23, and clips the value of the luminancesignal Y now inputted to the same value as the lower limit.

If it is determined that no request is made for changing the lower limitof the passband in Step S21 (that is, if it is notified that the lowerlimit is not changed), if it is determined that the value of theluminance signal Y now inputted is equal to or greater than the lowerlimit of the passband in Step S22, or if the value of the luminancesignal Y is clipped to the lower limit of the passband in Step S23, theluminance undershoot passband adjusting circuit 13 goes to Step S24, andsupplies the value of the luminance signal Y to the compression circuit15.

Subsequently, in Step S25, the luminance undershoot passband adjustingcircuit 13 determines whether the luminance signal Y is inputted fromthe luminance overshoot passband adjusting circuit 12. If it determinesthat the luminance signal Y is inputted, it goes to Step S21, andsimilarly performs the process steps after that for the inputtedluminance signal Y.

If it is determined that the luminance signal Y is not inputted from theluminance overshoot passband adjusting circuit 12 in Step S25, theluminance undershoot passband adjusting circuit 13 ends the process.

Next, the operation of the color difference passband adjusting circuit14 will be described with reference to a flow chart shown in FIG. 6.

In Step S31, the color difference passband adjusting circuit 14determines whether the input data passband control part 16 makes arequest for changing the range of the passband for the color differencesignals CB/CR in Step S3 in FIG. 3. If it determines that a request ismade, it goes to Step S32.

In Step S32, the color difference passband adjusting circuit 14determines whether the value of the color difference signals CB/CR nowinputted is greater than the requested upper limit of the passband orsmaller than the lower limit. If it determines that the value is greateror smaller, it goes to Step S33.

In Step S33, if the value of the color difference signals CB/CR nowinputted is greater than the upper limit of the requested passband, thecolor difference passband adjusting circuit 14 clips the value to thesame value as the upper limit, or if the value is smaller than the lowerlimit, it clips the value to the same value as the lower limit.

If it is determined that no request is made for changing the passband inStep S31 (that is, if it is notified that the passband is not changed),if it is determined that the value of the color difference signals CB/CRnow inputted is the value in the range of the passband in Step S32, orif it is determined that the value of the color difference signals CB/CRis clipped in Step S33, the color difference passband adjusting circuit14 goes to Step S34, and supplies the color difference signals CB/CR tothe compression circuit 15.

Subsequently, in Step S35, the color difference passband adjustingcircuit 14 determines whether the color difference signals CB/CR areinputted from the color signal generating circuit 11. If it determinesthat the color difference signals CB/CR are inputted, it returns to StepS31, and similarly performs the process steps after that for theinputted color difference signals CB/CR.

If it is determined that the color difference signals CB/CR are notinputted from the color signal generating circuit 11 in Step S35, thecolor difference passband adjusting circuit 14 ends the process.

As described above, it is requested to adjust the passband, and theluminance signal Y and the color difference signals CB/CR in therequested passband are compressed.

For example, in the cases in which it is desired to output the luminancesignal Y in the integer range of 16 to 240 and in which it is desired tocompress and output the color difference signals CB/CR in the integerrange of 1 to 254, the input data passband control part 16 requests theluminance overshoot passband adjusting circuit 12 to change the upperlimit of the passband for the luminance signal Y from 254 to 240, andrequests the luminance undershoot passband adjusting circuit 13 tochange the lower limit of the passband for the luminance signal Y from 1to 16.

In addition, the input data passband control part 16 notifies the colordifference passband adjusting circuit 14 that the passband is notchanged.

As shown in FIG. 7A, in response to the request, in the luminanceovershoot passband adjusting circuit 12, the luminance signal Y of 241and above is clipped to 240, whereas in the luminance undershootpassband adjusting circuit 13, the luminance signal Y of 15 and below isclipped to 16, whereby the passband for the luminance signal Y isadjusted.

In addition, in the color difference passband adjusting circuit 14, inresponse to the request from the input data passband control part 16, asshown in FIG. 7B, the inputted color difference signals CB/CR in therange of 1 to 254 are outputted as they are (in this case, it isadjusted to all bandpass).

As described above, the luminance signal Y and the color differencesignals CB/CR, both of them adjusted in their passbands, are compressedby the compression circuit 15.

As described above, for example, the passband for the luminance signal Ycan be adjusted in the integer range of 0 to 255 representable by eightbits, which is a wider range than the integer range of 16 to 235compliant to the BT.709 standards, whereas, for example, the passbandfor the color difference signals CB/CR can be adjusted in the integerrange of 0 to 255 representable by eight bits, which is a wider rangethan the integer range of 16 to 240 compliant to the BT.709 standards.Therefore, video data corresponding to the display performancecapabilities of the display device can be provided to the display devicethat can represent colors in a wider color gamut than predeterminedstandards such as BT.709.

In addition, the input data passband control part 16 controls theluminance signal Y or the passband for the color difference signalsCB/CR in accordance with the display performance capabilities of thetarget display device, but it may control the passband in accordancewith the luminance signal Y or the color difference signals CB/CR to beinputted.

Next, a series of the process steps described above may be performed byhardware or may be by software. In the case in which a series of theprocess steps is performed by software, a program configuring thesoftware is installed in a multipurpose computer.

Then, FIG. 8 shows an exemplary configuration of a computer in which aprogram performing a series of the process steps described above isinstalled.

The program can be recorded in advance on a hard disk 105 or a ROM 103as a recording medium incorporated in the computer.

Alternatively, the program can be temporarily or permanently stored(recorded) on a removable recording medium 111 such as a flexible disc,a CD-ROM (Compact Disc Read Only Memory), an MO (Magneto-optical) disc,a DVD (Digital Versatile Disc), a magnetic disc, and a semiconductormemory. The removable recording medium 111 like this can be provided asso-called package software.

Moreover, the program is installed into the computer through theremovable recording medium 111 as described above, as well as it can beinstalled into the hard disk 105 incorporated in the computer from adownload site through an artificial satellite for digital satellitebroadcast over radio transmission, or installed into the computerthrough a network such as a LAN (Local Area Network) and the Internetover cable transmission, or installed into the incorporated hard disk105 by receiving the program thus transmitted by a communicating part108 in the computer.

The computer has a CPU (Central Processing Unit) 102 therein. To the CPU102, an I/O interface 110 is connected through a bus 101. When a usermanipulates an input part 107 configured of a keyboard, a mouse, amicrophone, etc., to enter an instruction to the CPU 102 through the I/Ointerface 110, it runs the program stored in the ROM (Read Only Memory)103. Alternatively, the CPU 102 loads into a RAM (Random Access Memory)104 the program that is stored in the hard disk 105, the program that istransmitted through a satellite or a network, received at thecommunicating part 108, and installed in the hard disk 105, or theprogram that is read out of the removable recording medium 111 mountedon a drive 109 and installed into the hard disk 105 for implementation.Thus, the CPU 102 performs the process steps in accordance with the flowcharts described above, or runs the process steps performed by theconfigurations in the block diagrams shown.

Then, the CPU 102 outputs the process results from an output part 106configured of an LCD (Liquid Crystal Display) and a speaker through theI/O interface 110, etc., as necessary, or transmits the process resultsfrom the communicating part 108, or further records the process resultson the hard disk 105.

Here, in the specification, the process steps describing the program toallow the computer to run various processes are not necessarilyperformed in time series along the order described in flow charts, whichinclude the process steps performed in parallel or separately (forexample, parallel processing or processing by an object).

In addition, the program may be processed in a single computer, or maybe processed by a plurality of computers in distributed processing.Furthermore, the program may be forwarded to a remote computer forimplementation.

Moreover, an embodiment of the invention is not limited to theembodiments described above, which can be modified within the scope notdeviating from the teaching of an embodiment of the invention.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. A signal processing apparatus in which a luminance signal in a firstnumeric range is assigned to an integer value in a second integer rangethat is narrower than a first integer range representable by a pluralityof predetermined bits for representation, and a luminance signal andcolor difference signals are outputted in compliance with apredetermined standard in which a color difference signal in a secondnumeric range is assigned to an integer value in a third integer rangethat is narrower than the first integer range for representation, thesignal processing apparatus comprising: a luminance signal assigningmeans for assigning the luminance signal in the first numeric range toan integer value in a fourth integer range that is narrower than thefirst integer range and wider than the second integer range; a colordifference signal assigning means for assigning the color differencesignals in the second numeric range to an integer value in a fifthinteger range that is narrower than the first integer range and widerthan the third integer range; and an adjusting means for adjusting thefourth integer range in a range that is narrower than the first integerrange and wider than the second integer range, and adjusting the fifthinteger range in a range that is narrower than the first integer rangeand wider than the third integer range.
 2. A signal processing method inwhich a luminance signal in a first numeric range is assigned to aninteger value in a second integer range that is narrower than a firstinteger range representable by a plurality of predetermined bits forrepresentation, and a luminance signal and color difference signals areoutputted in compliance with a predetermined standard in which a colordifference signal in a second numeric range is assigned to an integervalue in a third integer range that is narrower than the first integerrange for representation, the signal processing method comprising thesteps of: assigning the luminance signal in the first numeric range toan integer value in a fourth integer range that is narrower than thefirst integer range and wider than the second integer range; assigningthe color difference signals in the second numeric range to an integervalue in a fifth integer range that is narrower than the first integerrange and wider than the third integer range; and adjusting the fourthinteger range in a range that is narrower than the first integer rangeand wider than the second integer range, and adjusting the fifth integerrange in a range that is narrower than the first integer range and widerthan the third integer range.
 3. A program which allows a computer toexecute an output process in which a luminance signal in a first numericrange is assigned to an integer value in a second integer range that isnarrower than a first integer range representable by a plurality ofpredetermined bits for representation, and a luminance signal and colordifference signals are outputted in compliance with a predeterminedstandard in which a color difference signal in a second numeric range isassigned to an integer value in a third integer range that is narrowerthan the first integer range for representation, the output processcomprising the steps of: assigning the luminance signal in the firstnumeric range to an integer value in a fourth integer range that isnarrower than the first integer range and wider than the second integerrange; assigning the color difference signals in the second numericrange to an integer value in a fifth integer range that is narrower thanthe first integer range and wider than the third integer range; andadjusting the fourth integer range in a range that is narrower than thefirst integer range and wider than the second integer range, andadjusting the fifth integer range in a range that is narrower than thefirst integer range and wider than the third integer range.
 4. A signalprocessing apparatus in which a luminance signal in a first numericrange is assigned to an integer value in a second integer range that isnarrower than a first integer range representable by a plurality ofpredetermined bits for representation, and a luminance signal and colordifference signals are outputted in compliance with a predeterminedstandard in which a color difference signal in a second numeric range isassigned to an integer value in a third integer range that is narrowerthan the first integer range for representation, the signal processingapparatus comprising: a luminance signal assigning unit configured toassign the luminance signal in the first numeric range to an integervalue in a fourth integer range that is narrower than the first integerrange and wider than the second integer range; a color difference signalassigning unit configured to assign the color difference signals in thesecond numeric range to an integer value in a fifth integer range thatis narrower than the first integer range and wider than the thirdinteger range; and an adjusting unit configured to adjust the fourthinteger range in a range that is narrower than the first integer rangeand wider than the second integer range, and adjusting the fifth integerrange in a range that is narrower than the first integer range and widerthan the third integer range.